最大值:select max(num) from table
第二大值:select max(num) from table
where num not in(select max(num) from table)
第三大值:select max(num) from table
where num not in(select max(num) from table
where num not in(select max(num) from table))
最小值:select min(num) from table
转载于:https://www.cnblogs.com/yangzhouyyz/p/5228801.html